1. Field of the Invention
The present invention relates to a shift-register circuit, and more particularly to a shift-register circuit applied in a liquid crystal display (LCD).
2. Description of the Related Art
FIG. 1 is a circuit diagram of a convention shift-register circuit. The shift-register circuit generates output signals Vout1˜Voutn for driving load device 141˜14n. The shift-register circuit comprises shift-register units 121˜12n. Each shift-register unit 121˜12n generates an output signal for driving the corresponding load device and triggering the subsequent shift-register unit.
The voltage level of the output signal is altered when an error occurs in the load device. If an error occurs in the output signal, the voltage level of other output signals of the shift-register is also altered.
If the output signal Vout1 is at a high voltage level, the load device 141 and shift-register units 122 are driven by the output signal Vout1. When an error occurs in the load device 141, the voltage level of the output signal Vout1 drops from high voltage to low voltage level, and the shift-register units 122 are no longer driven by the output signal Vout1 such that the shift-register units 232˜12n malfunction.
The conventional shift-register unit utilizes identical output signals to drive the load device and subsequent shift-register unit. The shift-register circuit will not generate the correct output signal when the load device changes the corresponding output signal of the shift-register unit.